RT9230

The RT9230 is a 4-in-one power controller optimizedfor high-performance microprocessor and computerapplications. The IC integrates two PWM controller,two linear controllers as well as monitoring andprotection functions into a 28-pin SOP package. Thefirst PWM controller regulates the microprocessorcore voltage with a synchronous buck converter,while the second PWM controller supplies thecomputer system's AGP 1.5V or 3.3V bus power witha standard buck converter. The first linear regulatorprovides power for the 1.5V GTL bus and the secondlinear regulator provides 1.8V power for theNorth/South Bridge core voltage and/or cachememory circuits.

The RT9230 features an Intel-compatible, TTL 5-bitprogrammable DAC that adjusts the core voltagefrom 2.1V to 3.5V in 0.1V increments and from 1.3Vto 2.05V in 0.05V steps. The 5-bit DAC has a typical±1% tolerance. The second PWM controller is user-selectable for output level of 1.5V and 3.3V with±2.5% accuracy. The linear controllers drivesexternal N-MOSFET or NPN bipolar for the passtransistor to provide fixed output voltages of 1.5V±3% and 1.8V ±3%.

The RT9230 monitors all the output voltages. APower -good signal is issued when the core voltageis within  ±10% of the DAC setting and the otherlevels are above their under-voltage levels.

Additional build-in over-voltage protection for thecore output uses the lower MOSFET to preventoutput voltage above 115% of the DAC setting. ThePWM over-current function monitors the outputcurrent using the voltage drop across the MOSFET'sRDS(ON), which eliminates the need for a currentsensing resistor.